Improvement in steam engines



ittici,

@geiten gieten atmft GEORGE I. WASHURN, VOF `lllfOlitCfE STE-R,MASSACHUSETTS.

Letters Patent No. 62,713, dated VIarcL 5,4 1867.

IMPROVEMENT IN STEAM ENGINES.

TO ALL WHOM IT MAY CONCERN:'

Be it known that I, GEORGE I. WASHB'UBN, of the city and county ofWorcester, and State of Massachusetts. have invented a new and usefulImprovement in Steam Engines; and I do hereby declare the following tobe a full, clear, and exact description of the same, suiicie'nt t0enable one skilled in the art to which the invention appcrtains to makeuse of it, reference heilig had to the accompanying drawings, which formapart of this specilication, and in whieh i Figure I is a'verticalsection on' the line :r at, fig.'

Figure 2 is a vertical section Von thelinc y y, fig. 1.

. Figure 3 is a horizontal section un the line z z, iig. 1. Figures 4,5, and 6 show the same application of steamfto an engine in which thepistons are annular, have two piston-rods, and the rod connecting thecross-head with the crank passes through the centre of the cylinder.

This engine has two double-acting pistons, each operating by itself-inits'steam cylinder, and attached to a pistou-rod which carries a valveof any suitable construction, operating in its own chamber. Each valvecontrols the action of the steam upon the double-acting piston in theopposite cylinder, and not that piston to which Ait is attached. A`valveupon the eduction port, or in the exhausty pipe, opening outwardly,closes lthe aperture against the reflux of exhaust steam. Thepiston-rods may be attached each to its own crank on a doublecrank-shaft, as in the drawings, or may both be attached to the samecrank, provided that in all cases they are so located in reference teeach other that, when one piston is at the end of its stroke, the valvegoverning the action of steam thereupon may be in the proper positionfor reversing thesaid motion. Thus, if the cylinders are placed parallelto each other, as in the drawings, it will be necessary to have adoublecrankshaft in order tomaintain the above relation between the valve andpiston, `but if-the .cylinders are placed in the saine-plane, and at anangle of ninety degrees with each other, the rods may be attached to thcsame crank, and a proper valve motion preserved.` In the first-mentionedinstance a benefit will result from shortening the steam passages, andin the'sccond I use but one crank. An angle of ninety degrees is foundbetween the two cranks or the two cylinders. If the two cylinders beplaced at an angleof ninety degrces'aiid both pistone operate upon asingle crank, the pipes which convey the steam from thc valves to thepistons may be flexible or jointed, each cylinder hanging upontrn-nnions,-and dispensing with cross-head ways and connecti'ng-rods.The two piston-rods may be attached directly to the crank, the valveaction remaining the same as before. The steam may be taken eitherthrough flexible orjointed pipe, or through thehollow trunnions; andexhaustedliliewise. Also the connecting pipes may be enclosed 'in achamber and heate'd by any suitable means, as steam, or the product-s ofcombustion as they pass from the boiler to prevent condensation of steamin the connecting passages. In this fom the enginewill have twooscillating cylinders, but the mutual action of the valves and pistonsis designed to be the same as in the drawings, when the cylinders arestationary Aand parallel, the valve on a given piston-rod controllingthe action of the steam on the piston of the other rod.

While I do not confine myself to a disk-valve, it is n necessary featureof my invention that the valve shall be attached to the piston-rod andmore with the piston to which it is attached, though its effectiveaction is upon the other piston in the other cylinder.y Thevalve-chamber and piston-chamber, ltraversed by a common piston-rod, areseparated by a cylinder head, which entirely divides them so -far as anyassociation of coaction is concerned, the valve action, though,isochronous with the piston niotior, having no immediate effect upon it.I donot rely upon any extraneous condenser for obtaining a partialvacuum before the piston, but afford the exhaust steam the means ofescaping with the maximum liberty and freedom, and provide acheck-.valve over the ports in the exhaust-chamber to admit the cfiiuxbut prevent the reflux of steam therethrough.

The steam as it rushes ont will drive the atmosphere before it=until itsmomentum is overcome, at which time thc pressure behind it and againsttheexhaust side of the piston will be less than the atmospheric pressureoutside, thereby obtaining a partial vacuum on the exhaustv side of thepiston. The steam passing freely ont will expend' its momentum indriving the air before it through the' exhaust port, and, at the instantthe momei tuuiis; expended, the minimum pressure upon the exhaust sideof the piston is attained. This check-valve on the exhaust port, or iiithe exhanstpipe, is not designed to constitute the space interveningbetween it and the ci; is 2 cylinder as acondenser-in any respect ordegree, but to prevent the reflux of the exhaust steam into thecylinder. The automatic check-valve thus placed in the exhaus'passageo1: on the exhaust port is opened by the ilow outward of the exhauststeam, and closed by the reflux of the same, or by its gravity,- or aspring, as soon as the force of the outgoing steam is insutlicient tokeep it open.` It is not designed to prevent the escape of the steam,and is only operative when the exhaust port is open. lts object is toutilize the partial exhaust produced by the rapid emptying of theexhaaist end of the cylinder."'l`hat a partial vacuum is thus producedin certain contingencies is recognized by high expert authority, and itis areasonable deduction from the nature of the case.

In some cases, wherean engine has but a short stroke and rapidrevolution of the crank, thc valve may not be necessary to make themoment-ary partial vacsium available, as the period during which the airand steam is held at hay preparatory to the reflux may be sufficient toenable the piston to complete its motion when the steam is reversed andthc exhaust-passage closed by mechanical means preparatory to theadmission of live Steam to that side of the piston which was lateiyinContact with the exhaust steam referred to. The rate of motion of thepiston bei'n-gknown, and the rapidity with which the exhaust steam willpass from the cylinder being calculable,

it is reasonable to suppose that the speed of the steam being so far inexcess ot' that of the piston which is following, a partial vacuum will,at a certain time, be formed before the'momentum of the outgoing exhauststeam is perfectly conterpoised by the resistance of the atmosphere. Insome cases, as I havesaid, this period may be suicient for the purposein short-stroke engines; but in others. which move more slowly, it is,or may b'e, useful to place upon the port or in the exhaust pipe avalreto prevent the redux, and make the partial vacuum thus pr duced moredistinctly and certainly utilizable, and to prolong it for a longerperiod. To make this partial vacuum fully available, the port should becomp'aratively'large, and the pipe of such a shape as to offer theleastpossible resistance to the passage of the steam, and also of such lengththat the steam may exert its momentum against the atmosphere before itleaves the pipe.

In' the drawings, A is one steam cylinder, and B a second cylinder,their axes being parallel in the drawings, but capable ofA otherarrangement, as I have before stated. At the end of cylinder A is avalve-chamber, C, and at the end of cylinder B is a valve-chamber, D.Traversing longitudinally' in cylinder A and valvechamber. C is apiston-rod, a, having upon it a'piston, E, and valve-disks ee. Similarlythe piston-rod b traverses in cylinder B and valve-chamber D, carryingthe pistonl F and valvefdisksff. The cylinder and valve-chambers thusarranged in -line with each other, are separated by a. partition' orcylinder-head through a steam'tight opening, in which thepiston-rodpasses. "Each piston-rod is connected byapitman and crank to the mainshaft, on which is a ily-.wheel and two belt pulleys, as represented,the main s-haft being supported on standards, and the cross-head at eachconnection of piston-rod and pitman having guides, as usual under suchconditions. G isthe induction pipe to the inductionchamber H, and I isthe eduction pipe from the exhaust-chamber J, K being eheck-valves toprevent the reflux of exhaust steam back into the cylinder, as has beenbefore4 referred to. Live steam from the boiler is constantly present inthe vinduction-chamber H, and communicates by ports with the chamber Cto the ou'ter faces of the disks e c', respectively, and communicateswith chamberD by a single port, 3, between the two disks ff. 4Theexhaust-chamber J' receives steam from chamber C through a single port,6, between" the valves e e', and from chamberD',.through two p'orts, 8,above and below the disks .f.f, respectively. The cylinderA receives andldischarges steam through the ports 10 and 11 alternately from chamberD, andthe cylinder B receives and discharges steam through ports 12v and13, alternately, from chamber-C, the ports being alternately inductionand eduction ports, and the pistons in each .case double-acting.Piston-rod a being down, and b athalf stroke descending, steam isadmitted above disk 'c Afrom vchamber H, and passes through port 12above piston F, the exhaust steam below .piston F passing out throughport 13 to valve-chan'iber Glbetween disks@ e', and thence through port6 t0 the' exhaust-chamber J. Steam admitted below disk e serves tobalance its pressure on the valve in the' chamber C. While this is beingeifected in cylinder B, steam is admitted from chamber H through port 3into valve-chamber D, between the disks ff', and will pass thencethroughport 11 under piston E, as soon as the port 1l is uncovered by the diskf, passing its I nid stroke, the point' of. reversal ofithcsteam onpiston E. As soon as this reversal occurs, the port 10 will be open forthe exhaust steam from above piston E, to pass out into chamber D abovedisksf, and thence through port 8 into exhaust-chamber K.Theexhaust-chamber K connects by two ports with chamber D, and by onewith chamber C, and the steam chamber connects by two ports with chamberc, and by one with chamber D. In each case the duplicate ports arerespectively above and below the disks in the valve-chamber and thesingle port between the said disks., The steam admitted between thedisks is thereby balanced in its action on them as a valve, and the sameis true of the admission of it to the outer faces of the two disks on agiven piston-rod. In lthe cylinders `it is admitted to the upper andlower faces alternately, and the reciprocating action thereby obtained.

The description having. been given at length of the action in onedirection, the order and means for induction and eduction, whileexecuting the return motion, will be readily understood by experts, towhom this specifica,- ton is addressed. The engine may be reversed byreversing the `functions of the steam and exhaust-chambers H J, exceptwhen using the check-valves K. The cylinders maybe vertical orhorizontal, inclined or oscillatingthe connections thelrminimumlengtlu-asin the drawings, or longer if the cylinders are notso closelyassociated. Several may-.beasscciated around a common shaft with acommon crank or cranks, H, disconnected, except as to their commonshaft. Each valve, in the arrangement to lsecure the minimum length ofports, is opposite to the piston, whose motion it regulates, so that (asshown) the piston E is above the valve c e', and the piston E below thevalve ff. Figs. 4, 5, and illustrate the same application of steam in anengine whose pistons are annular, having two piston-rods and theconnecting-rods, which extend from the cross-heads to the crlankspassing through the centresoi` the cylinders. This admits of a certaincompactness of arrangement not repdily attained in any other way. l y

Hrs-ving described my invention, what I claim therein ns new, end desireto secure by `Letters Patent, is as follows:

l. claini the nrralngement. upon one pistomrod, of the double-acting,operating piston in its own cylinder, and a. .valve oi' valves attachedto said piston-rod, and operating Within a, valvecl1'amber iu line withsaid cylinder, substantially as described.

2. claim the combination with each otherof tivo such arrangements, (asexpressed in the :rbove clnimJ tim valves attached to a given piston-rodill-each case governingV the induction and eduction ports of theopposite steam cylinder, in which reciproca-tes the other piston-rod,substantially as described.

3.- I claim a valve, operating in connection with un exhaust port orpipe to permit the egress of steam, and

prevent reflux thereof, for the purpose described.

' GEO. I. WASHBURN.

Witnesses:

A.. D. HoBAR'r, EDWARD MELLE'N.

